Method of plating and method of manufacturing a micro device

ABSTRACT

A method of plating, which allows compositions of plating patterns of a plurality of layers to be uniform without any operational complexity, is provided. The area of the plating layer electrodeposited including plating patterns is constant in each of the plurality of layers. Accordingly, a value of plating-current density is easily maintained constant without any special operation. Consequently, the plating patterns in each of the plurality of layers is easily formed to have an uniform composition.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of plating suitable forforming plating patterns of a plurality of layers, and relates to amethod of manufacturing a micro device suitable for manufacturing onethat includes the plating patterns of the plurality of layers.

2. Description of the Related Art

In producing various sorts of electronic circuit boards andsemiconductor device substrates, plating patterns, which are formed inthe shape of plurality of layers and having the same composition witheach other, may be formed on a limited portion of the substrate (objectto be plated). When configurations (occupation area) of the platingpatterns of the plurality of layers differ mutually, plating-currentdensity needs to be adjusted in each of the plurality of layers in theplating in spite of using a plating bath of the same component. Forexample, the plating-current density is adjusted by controllingelectrode area as shown in Japanese Laid-Open Patent Publication (Kokai)No. H11-1799, and Japanese Laid-Open Patent Publication (Kokai) No.H2-228493.

SUMMARY OF THE INVENTION

However, operation is very complicated if every formation of the platingpatterns needs adjustment of the plating-current density in each of theplurality of layers. Moreover, in spite of using a plating bath of theuniform component, compositions of the formed plating patterns tend tobe quite different from each other in each layer. Since such compositiondifference affects the property value of the plating pattern itself,such as magnetic property, it is expected to be minimized to a maximumextent.

The present invention has been devised in view of the above problem, andit is desirable to provide a method of plating, which allows thecompositions of the plating patterns of a plurality of layers to beuniformed enough in each of the plurality of layers without anyoperational complexity. It is also desirable to provide a method ofmanufacturing a micro device that includes the plating patterns of aplurality of layers so that the compositions of the plating patterns maybe uniformed enough in each of the plurality of layers without anyoperational complexity.

A method of plating and a method of manufacturing a micro deviceincludes a step of forming a plating layer including the plating patternin each of plurality of layers so that an area of the plating layerelectrodeposited is constant in each of the plurality of layers. Here,“the plating layer including the plating pattern” means that the platinglayer includes not only the aimed plating pattern but also otherportions.

According to the method of plating and manufacturing the micro device ofthe present invention, the area of the plating layer electrodeposited isconstant in each of the plurality of layers. As a result,plating-current density can be kept constant without any adjustment ofplating current or electrode area.

Preferably, the method of plating and the method of manufacturing themicro device includes steps of: forming a plating foundation layer ineach of the plurality of layers, forming a resist frame and an auxiliaryresist pattern on the plating foundation layer in each of the pluralityof layers, forming the plating layer selectively on the platingfoundation layer other than portions covered with the resist frame andthe auxiliary resist pattern in each of the plurality of layers,removing the resist frame and the auxiliary resist pattern in each ofthe plurality of layers, and removing the plating layer other than theplating pattern surrounded by the resist frame in each of the pluralityof layers, and sum total of the area of the resist frame and theauxiliary resist patterns in each of the plurality of layers isconstant. Preferably, at least one of geometry and the area of theplating pattern differs between the plurality of layers. Preferably, inthe formation process for each of the plurality of layers, a commonplating bath is used for forming the plating layer in each of theplurality of layers. Further, it is desirable to form a plurality of theauxiliary resist patterns symmetrically with respect to the resistframe. Further, preferably, the resist frame and the auxiliary resistpattern are formed to have a line width equal to each other. The linewidth here means a width of, a cross section orthogonal to alongitudinally-extending direction (longitudinal direction) of each ofthe resist frame and the auxiliary resist pattern.

According to the method of plating or method of manufacturing the microdevice of the present invention, since the area of the plating layerelectrodeposited, including the plating pattern, is made constant ineach of the plurality of layers, the plating patterns, each having acomposition uniformed enough in each of the plurality of layers, can beformed more easily, without changing any plating condition.

Other and further objects, features and advantages of the invention willappear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view showing a whole configuration of aplating device used for formation method of a layered film according toa first embodiment of the present invention.

FIG. 2A is a plan view and FIG. 2B is a partially enlarged view, eachshowing a configuration of a substrate appearing in FIG. 1.

FIG. 3 is a sectional view showing a cross-sectional configuration ofthe layered film formed using the plating device appearing in FIG. 1.

FIGS. 4A to 4C are plan views showing a configuration of each platingpattern in the layered film shown in FIG. 3.

FIG. 5 is a sectional view showing one production process of the layeredfilm shown in FIG. 3 using the plating device appearing in FIG. 1.

FIG. 6 is a sectional view showing another production process subsequentto FIG. 5.

FIG. 7 is a sectional view showing another production process subsequentto FIG. 6.

FIG. 8 is a sectional view showing another production process subsequentto FIG. 7.

FIGS. 9A to 9C are plan views of a resist pattern shown in FIG. 8.

FIG. 10 is a sectional view showing another production processsubsequent to FIG. 8.

FIG. 11 is a sectional view showing another production processsubsequent to FIG. 10.

FIG. 12 is a sectional view showing another production processsubsequent to FIG. 11.

FIG. 13 is a sectional view showing another production processsubsequent to FIG. 12.

FIG. 14 is a sectional view showing another production processsubsequent to FIG. 13.

FIG. 15 is a sectional view showing another production processsubsequent to FIG. 14.

FIGS. 16A to 16C show a first modification with regard to a plan viewconfiguration of the resist pattern shown in FIG. 9.

FIGS. 17A to 17C show a second modification with regard to the plan viewconfiguration of the resist pattern shown in FIG. 9.

FIGS. 18A to 18C show a third modification with regard to the plan viewconfiguration of the resist pattern shown in FIG. 9.

FIGS. 19A to 19C show a fourth modification with regard to the plan viewconfiguration of the resist pattern shown in FIG. 9.

FIGS. 20A to 20C show a fifth modification with regard to the plan viewconfiguration of the resist pattern shown in FIG. 9.

FIG. 21 is an exploded perspective view showing a configuration of athin film magnetic head, which is formed by a method of manufacturingthe same according to a second embodiment of the present invention.

FIG. 22 is a sectional view showing a configuration taken along the lineXXI-XXI of the thin film magnetic head shown in FIG. 21, which is seenfrom the direction indicated by arrows.

FIG. 23 is a plan view showing one production process in the method ofmanufacturing the thin film magnetic head shown in FIG. 21.

FIG. 24 is a plan view showing another production process subsequent toFIG. 23.

FIG. 25 is a sectional view showing another production processsubsequent to FIG. 24.

FIG. 26 is a plan view showing another production process subsequent toFIG. 25.

FIG. 27 is a sixth modification with regard to the plan viewconfiguration of the resist pattern shown in FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the invention will be described in detail hereinbelowwith reference to the drawings.

First Embodiment

First, a plating device for implementing a formation method of a layeredfilm as a first embodiment of the present invention, and an electrodeassembly arranged therein will be described hereinbelow with referenceto FIGS. 1 to 4.

FIG. 1 is a schematic sectional view showing a configuration of theplating device. The plating device forms a plating layer on a surface11S (surface to be plated) of a substrate 11, which is an object to beplated, and includes a plating liquid vessel 30 which contains a platingbath 31, and a cathode electrode assembly 10 and an anode electrodeassembly 20 disposed in the plating liquid vessel 30, so as to beopposed to each other via the plating bath 31. The cathode electrodeassembly 10 is attached firmly to a bottom 32 of the plating liquidvessel 30 so that the plating bath 31 may not leak. The cathodeelectrode assembly 10 has an aperture 10K, and the substrate 11 in theshape of a thin plate is disposed therein to cover the aperture 10K. Thesubstrate 11 is supported by a supporting body 50 which includes a stage51 and a cylinder 52 so that the surface 11S is in contact with theplating bath 31. The plating bath 31 has a composition in accordancewith a sort of plating layer to be obtained. The plating device furtherhas a power unit 70. The power unit 70 is electrically connected withthe cathode electrode assembly 10 and the anode electrode assembly 20 bylead wires 71 and 72 respectively to apply direct current voltagebetween the electrodes. Although the power unit 70 of a type thatapplies direct current voltage is illustrated herein, it is not limitedto this but what applies alternating voltage or pulse voltage can beused.

The anode electrode assembly 20 includes an anode 21, an anode cylinder22 having the anode 21 attached to one end thereof, and a supporter 23for fixing the other end of the anode cylinder 22 to an upper portion 33of the plating liquid vessel 30. The anode 21 is arranged so as to facewith the surface 11S via the plating bath 31, and is connected with thepower unit 70 by the lead wire 72 passing through the anode cylinder 22and the supporter 23.

In this plating device, a plating seed layer covers the surface 11S ofthe previously-formed substrate 11 to form the plating layer on thesubstrate, by applying direct current voltage between the cathodeelectrode assembly 10 and the anode electrode assembly 20 using thepower unit 70, when the plating liquid vessel 30 is filled with theplating bath 31 as shown in FIG. 1.

Subsequently, the formation method of the layered film using thisplating device will be explained with reference to FIGS. 2 to 15.

Here, a case where layered film 1 (which will be described later) areformed on each of a plurality of element fields R1 one-by-one on thesubstrate 11 as schematically shown in FIGS. 2A and 2B, is explained forexample.

FIG. 2A illustrates a whole configuration of the substrate 11. In FIG.2A, each rectangular area R3, which is defined by dividing the substrate11 into matrix, is equal to a range to be exposed by one operation of astepper and so on (that is, an exposure region which can be exposed inone shot of the stepper), for example. FIG. 2B is an enlarged view ofany one of the rectangular areas R3. The rectangular area R3 includes aplurality of unit fields R4 of a rectangular shape, that are defined byplurality of scribe lines L1 and L2. Each unit field R4 includes anelement field R1 and a gap field R2 surrounding the element field R1.With such arrangement, the element fields R1 are arranged in matrix andequally spaced at specified intervals.

As shown in FIG. 3, the layered film 1 are formed by layering in order afirst layer L1 that includes a plating pattern M1, a second layer L2that includes a plating pattern M2, and a third layer L3 that includes aplating pattern M3. Peripheries of the plating patterns M1 to M3 aresurrounded by insulating layers Z1 to Z3, respectively. The surfaces ofthe plating pattern M1 and the insulating layer Z1 form a coplanar face,the surfaces of the plating pattern M2 and the insulating layer Z2 forma coplanar face F2, and the surfaces of the plating pattern M3 and theinsulating layer Z3 form a coplanar face F3. As shown in FIGS. 4A to 4Cfor example, the plating patterns M1 to M3 are all rectangular in planview, but have different dimensions from each other. Namely, occupationareas of the plating patterns M1 to M3 are different from each other.However, they all have a similar composition. FIG. 3 is a sectional viewshowing a layered structure of the layered film 1, and FIGS. 4A to 4Care plan views showing configurations of the plating patterns M1 to M3in plan view. Namely, FIG. 3 corresponds to cross sections taking alongthe lines III-III of FIGS. 4A to 4C.

Formation process of the plating pattern M1 is as follows. As firstshown in FIG. 5, the substrate 11 is prepared as an object to be plated4. Then, as shown in FIG. 6, a plating foundation layer 12 is formed tocompletely cover the surface 11S of the substrate 11. The platingfoundation layer 12 is formed with component materials such as nickeliron alloy (NiFe) by vacuum deposition method such as sputtering, forexample.

Subsequently, after forming a photoresist layer 13Z so as to cover asurface of the plating foundation layer 12 completely, a photoresistpattern 13A is formed using photolithographic technique, as shown inFIG. 7. Specifically, first, a latent image portion 13K is formed byselectively exposing the photoresist layer 13Z via a photo mask 14 whichhas an aperture 14K of a specified shape. Subsequently, after performingheat-treatment as necessary, it is developed by dissolving and removingthe latent image portion 13K using a specified developer, and further,is washed and dried. In this manner, the photoresist pattern 13A of aspecified shape is completed.

As shown in FIG. 9 (A), photoresist patterns 13B to 13G, as an auxiliarypattern, are formed together with the formation of the photoresistpattern 13A. FIG. 9A is plan view showing a planar configuration andlayout of the photoresist patterns 13A to 13G (hereinafter genericallycalled photoresist pattern 13). Namely, FIG. 8 corresponds to a crosssection taking along the line VIII-VIII of FIG. 9A, seen from thedirection indicated by an arrow. The photoresist pattern 13A is disposedso as to surround a portion R13A in which the plating pattern M1 will beformed (hereinafter called formation portion) Meanwhile, it is preferredthat the other photoresist patterns 13B to 13G are disposedsymmetrically with respect to the photoresist pattern 13A so that thephotoresist pattern 13A may be centered. In this case, it is desirablethat geometries and dimensions of each pair of themutually-symmetrically disposed photoresist patterns of the photoresistpatterns 13B to 13G are equal to each other, and a part of thephotoresist patterns 13B to 13G is W1, which is equal to a part of thewidth of the photoresist pattern 13A. Here, it is defined that anauxiliary portion R13B is an area excluding the portions occupied by thephotoresist pattern 13 and the formation portion R13A from the unitfield R4. Accordingly, sum total of the formation portion R13A and theauxiliary portion R13B are taken as an area to be plated, denoted by aplating portion R13.

After forming the photoresist pattern 13, plating is processed using theaforementioned plating device, and as shown in FIG. 10, a plating layer15 made of NiFe is formed. The plating layer 15 is formed so as tooccupy the plating portion R13 shown in FIG. 9A. At this time, thephotoresist pattern 13A works as a photoresist frame defining theoutline of the plating pattern M1, which will be obtained eventually.

After the formation of the plating layer 15, the plating foundationlayer 12 is partially exposed by removing the photoresist pattern 13using an organic solvent as shown in FIG. 11. Further, an exposedportion R12 of the plating foundation layer 12 is removed by milling orthe like, using the plating layer 15 as an etching mask. In this manner,as shown in FIG. 12, the surface 11S of the substrate 11 is partiallyexposed.

Subsequently, after selectively forming a photoresist pattern 16 so asto cover the formation portion R13 and the exposed surface 11S as shownin FIG. 13, the plating layer 15 that is not covered by the photoresistpattern 16 is removed by wet etching as shown in FIG. 14. Finally, asshown in FIG. 15, the plating pattern M1, which is formed on theformation portion R13 constituted by the plating layer 15 and theplating foundation layer 12A, appears by removing the photoresistpattern 16 with an organic solvent or the like.

Formation process of each plating patterns M1-M3 is substantially thesame. Namely, the process of forming the plating pattern M2 on theplating pattern M1 is as follows. First, an electrical insulatingmaterial such as aluminium oxide (Al₂O₃) is formed in the state of FIG.15 so that the periphery of the plating pattern M1 may be fully filledup, for example. Subsequently, flattening is performed until a surfaceof the plating pattern M1 is exposed so that the coplanar face F1 thatis formed by the plating pattern M1 and the insulating layer Z1 isobtained. After this, the plating pattern M2 is formed by repeating eachformation process of FIGS. 6 to 15. Similarly, the plating pattern M3 islayered on the coplanar face F2 formed by the plating pattern M2 and theinsulating layer Z2, thereby completing the layered film 1 shown in FIG.3.

In forming each of the plating patterns M1 to M3, one or morephotoresist patterns are formed so that a total occupation area of eachof the plating patterns may be equal to each other, and plating processis selectively performed using the same plating bath 31. Morespecifically, in forming the plating pattern M2, photoresist patterns17B to 17G are formed as an auxiliary pattern, together with theformation of a photoresist pattern 17A, as shown in FIG. 9B. Thephotoresist pattern 17A is disposed so as to surround a portion R17A inwhich the plating pattern M2 will be formed (hereinafter called asformation portion R17A), and works as a photoresist frame defining theoutline of the plating pattern M2. FIG. 9B is a plan view showing aconfiguration of the photoresist patterns 17A to 17G (hereinaftergenerically called photoresist pattern 17) in plan view. Herein, sumtotal of the occupation areas of the photoresist pattern 17 is madeequal to that of the photoresist pattern 13. In other words, theoccupation area of a plating portion R17, which is sum total of theformation portion R17A and an auxiliary portion R17B, is made equal tothe occupation area of the plating portion R13.

Also, the plating pattern M3 is formed in a similar way. As shown inFIG. 9C, photoresist patterns 18B and 18C as an auxiliary pattern areformed together with a photoresist pattern 18A as a photoresist frame.The photoresist pattern 18A is disposed so as to surround a portion(formation portion) R18A in which the plating pattern M3 will be formed,and works as a photoresist frame defining the outline of the platingpattern M3. FIG. 9C is a plan view showing a configuration of thephotoresist patterns 18A to 18C (hereinafter generically calledphotoresist pattern 18) in plan view. Herein, sum total of theoccupation areas of the photoresist pattern 18 is made equal to that ofthe photoresist pattern 13, and that of the photoresist pattern 17,respectively. Namely, the occupation area of a plating portion R18,which is sum total of the formation portion R18A and an auxiliaryportion R18B, is made equal to the occupation area of the platingportion R13, and the occupation area of the plating portion R17,respectively.

As described above, in the present embodiment, since the sum total ofthe occupation areas of the photoresist pattern 13, the sum total of theoccupation areas of the photoresist pattern 17, and the sum total of theoccupation areas of the photoresist pattern 18 are all equal to eachother, an area of each of the plating portions R13, R17 and R18, usedfor the plating process of the plating patterns M1 to M3, that is, anelectrodeposition area, is always made equal to each other. Accordingly,plating-current density can be easily kept constant without changing acurrent value. As a result, the plating patterns M1-M3 of an almostidentical composition can be formed quite efficiently. In particular,difference in composition can be suppressed substantially when theauxiliary patterns such as the photoresist patterns 13B to 13G arearranged evenly around the photoresist frame such as the photoresistpattern 13A.

<Modification>

Layout of the photoresist patterns 13, 17 and 18 are not limited tothose shown in FIGS. 9A to 9C, and various modifications are available.Hereafter, some modifications of the present embodiment are shown.

A first modification shown in FIGS. 16A to 16C is that the photoresistpatterns 13 and 17 are respectively formed on the basis of thephotoresist pattern 18A, which defines the outline of the largestplating pattern M3 so that sum totals of the occupation areas of thephotoresist patterns 13 and 17 may be equal to the occupation area ofthe photoresist pattern 18A, respectively. Namely, in forming theplating pattern M3, only the photoresist pattern 18A working as aphotoresist frame is formed, and formation of the other portionscorresponding to the photoresist patterns 18B and 18C shown in FIG. 9Cis omitted. On the other hand, in the cases of FIGS. 16A and 16B, fourphotoresist patterns 13B to 13E (or 17B to 17E) are formed as anauxiliary pattern. Here, the photoresist patterns 13B to 13E are allidentical in shape and dimension, and are arranged symmetrically withrespect to the central photoresist-pattern 13A as shown in FIG. 16A.Similarly, the photoresist patterns 17B to 17E are all identical inshape and dimension, and are arranged symmetrically with respect to thecentral photoresist-pattern 17A as shown in FIG. 16B.

In a second modification shown in FIGS. 17A to 17C, the auxiliarypattern is provided in the gap field R2 instead of the element field R1.Also in this case, the occupation area of the photoresist pattern 18A isequal to sum total of the photoresist patterns 13A to 13E, and that ofthe photoresist patterns 17A to 17E, respectively.

Similarly, in a third modification thereof shown in FIGS. 18A to 18C,the auxiliary pattern is provided in the gap field R2. Also in thiscase, sum total of the occupation areas of the photoresist patterns 13Ato 13K, that of the photoresist patterns 17A to 17G, and that of thephotoresist patterns 18A to 18C, are all equal to each other.

In a fourth modification shown in FIGS. 19A to 19C and a fifthmodification shown in FIG. 20A to 20C, the auxiliary pattern is providedin both of the element field R1 and the gap field R2. Also in thesecases, sum total of the occupation areas of the photoresist pattern 13,that of the photoresist pattern 17, and that of the photoresist pattern18, are all equal to each other.

Second Embodiment

Subsequently, a thin film magnetic head and method of manufacturing thesame will be described with reference to FIGS. 21 to 26, according to asecond embodiment of the present invention.

The thin film magnetic head of the second embodiment includes aplurality of plating patterns such as a lower shielding layer and anupper shielding layer, respectively formed in layers different from eachother. First, a schematic configuration of the thin film magnetic headis explained hereinbelow, and detailed description of the shieldinglayers will be given later.

FIG. 21 is an exploded perspective view showing a configuration of athin film magnetic head 110 formed on one side of a slider in a magnetichead device. FIG. 22 is a sectional view showing a configuration takenalong the line XXI-XXI of FIG. 21, seen from the direction indicated bythe arrow. As shown in FIGS. 21 and 22, the thin film magnetic head 110is formed by layering a read head portion 110A and a write head portion110B in order from a side close to a substrate 100 of the slider. Thewrite head portion 110B writes magnetic information on a magneticrecording medium, and the read head portion 110A reproduces the magneticinformation written on the magnetic recording medium.

As shown in FIGS. 21 and 22, the read head portion 110A is configured insuch a manner that, on a side exposed to an air bearing surface(hereinafter called ABS) 100F, a lower shielding layer 111, a lower gaplayer 112, a magnetoresistive (hereinafter called MR) element 110C, anupper gap layer 120 and an upper shielding layer 121 are layered inorder on the substrate 100, for example.

The MR element 110C includes a magnetoresistive film pattern(hereinafter called MR film pattern) 114, a pair of magnetic domaincontrolling layers 115L and 115R extending on the both sides of the MRfilm pattern 114, and a pair of conductive lead layers 116L and 116Rformed on the pairs of magnetic domain controlling layers 115L and 115respectively. The MR film pattern 114 has a spin valve structure, whichis typically configured in such a manner that a foundation layer, apinning layer, a pinned layer, a non-magnetic layer, a free layer and acap layer and so on are layered in order on the lower gap layer 112. TheMR film pattern 114 functions as a sensor for reading the informationwritten on the magnetic recording medium. The pair of magnetic domaincontrolling layers 115L and 115R and the pair of conductive lead layers116L and 116R are arranged so that they may be opposed to each other onboth sides of the MR film pattern 114 along a direction corresponding toa direction of a write track width of the magnetic recording medium(that is, X-direction). The magnetic domain controlling layers 115L and115R, which are typically formed by a hard magnetic material containinga cobalt platinum alloy (CoPt) or the like, arrange magnetic domaindirections of free layers included in the MR film pattern 114 into asingle domain so as to suppress generation of a Barkhausen noise. Theconductive lead layers 116L and 116R, which are typically made of copper(Cu) or the like, work as a current path sending a sensing current tothe MR film pattern 114 in a direction orthogonal to the layereddirection (that is, X-direction), and, as shown in FIG. 21, areconnected to electrodes 116LP and 116RP, respectively.

The lower shielding layer 111 is typically made of a magnetic materialsuch as a nickel iron alloy (NiFe), and works so that the MR filmpattern 114 may not be affected by unnecessary magnetic field. The lowergap layer 112 is made of an electrical insulating material such asaluminium oxide (Al₂O₃) and alumimium nitride (AlN), and is intended forelectrical insulation between the lower shielding layer 111 and the MRfilm pattern 114. Upper gap layer 120 is also made of an electricalinsulating material as with the lower gap layer 112, and is intended forelectrical insulation between the upper shielding layer 121 and the MRfilm patterns 114. The upper shielding layer 121 is made of a magneticmaterial such as a nickel iron alloy (NiFe) as with the lower shieldinglayer 111, and works so that the MR film pattern 114 may not be affectedby unnecessary magnetic field. The upper shielding layer 121 also worksas a lower magnetic pole in the write head portion 110B. It is to benoted that another lower magnetic pole may be provided separately fromthe upper shielding layer 121.

In the read head portion 110A configured in this manner, a magnetizationdirection of the free layer of the MR film pattern 114 changes inaccordance with a signal magnetic field applied from the magneticrecording medium. Accordingly, a magnetization direction of the pinnedlayer included in the MR film pattern 114 changes relatively. In thiscase, variation of magnetization directions is expressed by variation ofelectric resistance by sending the sensing current to the MR filmpattern 114 via the pair of conductive lead layers 116L and 116R. Withthis, the signal magnetic field is detected to read magneticinformation.

The write head portion 110B includes the upper shielding layer 121, awrite gap layer 141, a pole chip 142, a coil 143, a photoresist layer144, a connecting portion 145 and an upper magnetic pole 146, as shownin FIGS. 21 and 22.

The write gap layer 141 is made of an electrical insulating materialsuch as Al₂O₃ and AlN, and is formed on the upper shielding layer 121.The write gap layer 141 has an aperture 141A for formation of a magneticpath in a position corresponding to the center of the coil 143 in theXY-plane (refer to FIG. 21). The coil 143 is formed in the shape of aspiral in plan view around the aperture 141A on the write gap layer 141.Further, the photoresist layer 144 is formed in a specified pattern soas to cover the coil 143. Here, the photoresist layer 144 has been curedin advance by heat-treatment. Terminals of the coil 143 are connected toelectrodes 143S and 143E, respectively. The pole chip 142 is arrangedbetween the coil 143 covered with the photoresist layer 144 on the writegap layer 141 and the ABS100F. The connecting portion 145 is arranged soas to cover the aperture 141A.

The upper magnetic pole 146, which is made of a magnetic material havinga high saturation magnetic flux density such as a NiFe alloy or ironnitride (FeN), is formed so as to cover the pole chip 142, thephotoresist layer 144 and the connecting portion 145. The upper magneticpole 146 connects the pole chip 142 and the connecting portion 145magnetically, and further, is in contact with the upper shielding layer121 via the connecting portion 145 to be magnetically connectedtherewith. Although not illustrated, it is to be noted that an overcoatlayer made of Al₂O₃ and so on covers the whole upper surface of thewrite head portion 110B.

The write head portion 110B with such configuration writes informationin such a manner as follows. Magnetic flux is generated by currentsflowing through the coil 143 in the magnetic path constructed mainly bythe upper shielding layer 121 and the upper magnetic pole 146. Themagnetic flux then produces a signal magnetic field around the write gaplayer 141, and the signal magnetic field magnetizes the magneticrecording medium to write information thereon.

Next, method of manufacturing the thin film magnetic head 110 will beexplained.

First, whole picture of the method of manufacturing the thin filmmagnetic head 110 is explained with reference to FIGS. 21 and 22.

First, after forming the lower shielding layer 111 which is typicallymade of NiFe by electroplating on the substrate 100, the lower gap layer112 is formed by sputtering or the like on the lower shielding layer111. Next, a multilayer film which will become the MR film pattern 114is formed on the lower gap layer 112. Specifically, the foundationlayer, the pinning layer, the pinned layer, the non-magnetic layer, thefree layer and the cap layer, all of which are not illustrated, arelayered in order by sputtering or the like. Then, the multilayer film isselectively etched by photolithographical patterning, ion milling andthe like, to form the MR film pattern 114. After this, the pair ofmagnetic domain controlling layers 115L and 115R are formed on the lowergap layer 112 so that they may be opposed to each other on both sides ofthe MR film pattern 114. Further, the conductive lead layers 116L and116R are formed on the magnetic domain controlling layers 115L and 115R,respectively. Subsequently, the upper gap layer 120 is formed bysputtering for example so as to cover the whole body. Finally, the uppershielding layer 121, which is typically made of NiFe, is selectivelyformed by electroplating on the upper gap layer 120, and formation ofthe read head portion 110A is generally completed.

Subsequently, the write head portion 10B is formed on the read headportion 110A.

Specifically, first, the write gap layer 141 is selectively formed onthe upper shielding layer 121 by sputtering or the like, and ispartially etched to form the aperture 141A for forming the magneticpath. Next, the pole chip 142 is formed on the write gap layer 141 onthe ABS100F side by electroplating, and the connecting portion 145 isformed by electroplating so that the aperture 141A may be covered.Further, the coil 143 of a spiral shape is formed around the aperture141A, then the photoresist layer 144 is formed in a specified pattern sothat the coil 143 may be covered, and is cured by heat-treatment. Afterforming the photoresist layer 144, the upper magnetic pole 146 isselectively formed so as to connect the pole chip 142 and the connectingportion 145. In this manner, formation of the write head portion 110B isgenerally completed.

Finally, the overcoat layer which is not illustrated is formed so as tocover all the foregoing structures including the upper magnetic pole146. In this manner, formation of the thin film magnetic head 110 whichis constituted by the read head portion 110A and the write head portion110B is completed.

Subsequently, formation process of the lower shielding layer 111 and theupper shielding layer 121 is explained in detail with reference to FIGS.23 to 26. FIGS. 23 to 26 is a plan view showing each production processwhen the lower shielding layer 111 and the upper shielding layer 121 areformed.

In forming the lower shielding layer 111, s plating foundation layer(not shown) which is made of NiFe is formed so that a surface of thesubstrate 100 may be covered. Subsequently, after forming a resist layer(not shown) so that the whole plating foundation layer may be covered, aphotoresist pattern 113A of a specified shape as shown in FIG. 23 isformed by photolithography.

Photoresist patterns 113B to 113I, which are configured and arranged asshown in FIG. 23, are formed simultaneously with the formation of thephotoresist pattern 113A. The photoresist pattern 113A as a photoresistframe is disposed so as to surround a portion R113A in which the lowershielding layer 111 will be formed (hereinafter called formationportion). The photoresist patterns 113B to 113I as an auxiliary patternare desirably disposed symmetrically each other with respect to thephotoresist pattern 113A. In FIG. 23, the photoresist pattern 113B vs.the photoresist pattern 113I, the photoresist pattern 113C vs. thephotoresist pattern 113H, the photoresist pattern 113D vs. thephotoresist pattern 113G, and the photoresist pattern 113E vs. thephotoresist pattern 113F are arranged symmetrically, respectively. It isfurther desirable that configurations and dimensions of the photoresistpatterns 113B to 113I are all equal to each other, and a part of thewidth thereof is equal to a part of the width of the photoresist pattern113A. Here, it is defined that an auxiliary portion R113B is an areaexcluding the areas occupied by the photoresist pattern 113 (photoresistpatterns 113A to 113I) and the formation portion R113A from the unitfield R4. Accordingly, sum total of the formation portion R113A and theauxiliary portion R113B are taken as an area to be plated, denoted bythe plating portion R113.

After forming the photoresist pattern 113, plating is performed usingthe foregoing plating device to form a plating layer (not shown) made ofNiFe so that the plating portion R113 may be occupied therewith. Thenthe lower shielding layer 111 of a specified shape, which is formed bythe plating layer and the plating foundation layer and formed on theformation portion R113A, is obtained as with the above-mentioned firstembodiment (refer to FIG. 24).

The upper shielding layer 121 can be formed as with the case of thelower shielding layer 111. Namely, after forming a plating foundationlayer (not shown) made of NiFe so that the surface of the upper gaplayer 120 may be covered, photoresist patterns 117A to 117K (hereinaftergenerically called photoresist pattern 117) of a specified shape arearranged in a specified position as shown in FIG. 25. The photoresistpattern 117A is disposed so as to surround a portion R117A in which theupper shielding layer 121 will be formed (formation portion), and worksas a photoresist frame for defining the outline of the upper shieldinglayer 121. On the other hand, photoresist patterns 117B to 117K works asan auxiliary pattern. After forming the photoresist pattern 117, theupper shielding layer 121 of the specified shape, which is formed by theplating layer and the plating foundation layer and formed in theformation portion R117A, is obtained as with the case of the lowershielding layer 111 (refer to FIG. 26).

Here, it is defined that an auxiliary portion R117B is an area excludingthe areas occupied by the photoresist pattern 117 and the formationportion R117A from the unit field R4. Herein, sum total occupation areaof the photoresist pattern 117 is made equal to that of the photoresistpattern 113; In other words, the occupation area of a plating portionR117, which is the sum total of the formation portion R117A and theauxiliary portion R117B, is made equal to the occupation area of theplating portion R113.

In the second embodiment of the present invention, as described above,since sum total of the occupation area of the photoresist pattern 113and that of the photoresist pattern 117 are equal to each other, anelectrodeposition area, which is an area to be plated with platinglayer, is also equal in each layer of the thin film magnetic head.Accordingly, a value of plating-current density can be kept constanteasily without changing a current value. As a result, the lowershielding layer 111 and the upper shielding layer 121, which have analmost same composition each other, can be formed very efficiently.

FIRST EXAMPLE

A detailed example of the present invention will be explainedhereinbelow.

In the following example (a first example) of the present invention, alayered film was produced by plating technique with use of a photoresistpattern corresponding to that shown in the fifth modification (FIGS. 20Ato 20C) of the above-mentioned first embodiment.

Specifically, the plating patterns M1 to M3 made of NiFe wererespectively formed to have an average thickness of 2 μm respectively,in a specified region R1 of 900 μm×400 μm on a silicon substrate (platedsubstrate) of 6 inches in diameter. Plane sizes of the plating patternsM1 to M3 will be indicated later in Table 1. Width of each gap field R2was 200 μm. The plating foundation layer 12 was formed to have anaverage thickness of 0.03 μm by sputtering. In forming the photoresistlayer, “AZ5105P” of AZ Electronic Materials' product was used as aphotoresist material and applied, then was heat-treated for 90 secondsat 100 degrees C. Further, the latent image portion was formed using“NSR-EX 14C (DUV)”, an exposure product of NIKON CORP. The exposingcondition was set to: numerical aperture (NA): 0.6, diaphragm σ(ratio ofillumination to lens NA): 0.6. After exposure, development wasaccomplished using an aqueous alkaline solution (2.38% aqueoustetramethylammonium hydroxide (TMAH)). Width W1 of each photoresistpatterns 13A, 17A and 18A as a photoresist frame was 20 μm. Surfaceratio of each plating portion (R13, R17, R18) to the unit field R4 wasset to 85.6% in each of the first to third layers L1 to L3, as shown inTable 1. A Watts-type nickel (N1) bath, added by iron ion, was used asthe plating bath 31. The unnecessary plating layer 15 formed in each ofthe auxiliary portions R13B, R17B, and R18B was removed by wet etchingwith use of a ferric chloride solution as etching solution. Further,each photoresist pattern was removed with use of acetone orN-methylpyrrolidone (NMP).

Composition of the layered film, which was produced in the first exampleon the aforementioned condition, was confirmed in comparison with thatof a first comparative example using a microscopicfluorescent-X-ray-spectrographic-analysis apparatus “JSM-6600F” of JEOLCo., Ltd. Here, the average content of nickel element in five arbitraryplaces was measured in each of the plating patterns M1 to M3. Resultsare shown in Table 1 with manufacturing conditions. In addition, a casewhere layered film including the plurality of plating patterns wereproduced by plating only with use of the photoresist frame and withoutany auxiliary pattern at all, is shown as the first comparative examplein Table 1. Set current of power supply was set to 2.8 A in the firstexample, and 3.0 A in the first comparative example.

TABLE 1 Surface Ratio Plane Size Width of of Ni Content of PlatingPhotoresist Metal-plated of Plating Layers Pattern Frame Portion PatternExample 1 First 50 μm × 50 μm 20 μm 85.6% 81.5% layer Second 50 μm × 100μm 20 μm 85.6% 81.5% layer Third 50 μm × 150 μm 20 μm 85.6% 81.5% layerComparative First 50 μm × 50 μm 20 μm 91.7% 81.5% Example 1 layer Second50 μm × 100 μm 20 μm 88.7% 81.2% layer Third 50 μm × 150 μm 20 μm 85.8%80.9% layer

FIRST EXAMPLE

As shown by Table 1, it was confirmed that, in the case of the firstcomparative example, the nickel content decreased according to thereduction of the surface ratio of each of the Plating portions(electrodeposition areas). On the other hand, in the case of the firstexample, it was confirmed that the nickel content was equal in each ofthe Plating patterns (namely, the composition ratio of Ni to Fe wasequal in each pattern) because surface ratio of the Plating portion(electrodeposition area) was uniformed in each of the first to the thirdlayers. Thus, it proves that the plating method of the present inventionis effective when the planar configuration and occupation area of theplating pattern is different in each layer.

As mentioned above, although the present invention has been explainedwith reference to some embodiments and examples (hereinafter genericallycalled embodiments), the present invention is not limited to theembodiments, and various kinds of modifications are available. Forexample, although the above-mentioned embodiments explain the caseswhere the plating patterns M1 to M3 are layered continuously, it is notlimited to this. For example, an arbitrary intervening layer, which isformed by a method other than the electroplating method, such assputtering, may be disposed therebetween. In that case, the interveninglayer may be a plating layer or may be an insulating layer. Besides, inthe above-mentioned embodiments, although one plating pattern is formedin each layer, a plurality of plating patterns may be formedcollectively in each layer. For example, the present invention is alsoapplicable to a case where a photoresist frame 19A surrounding aformation portion R19A of a rectangular shape and a photoresist frame19B surrounding a formation portion R19B of an elliptical shape areformed in the same layer to collectively produce a plating pattern ofthe rectangular shape and a plating pattern of the elliptical shape withuse of the photoresist frames 19A and 19B, as shown in a sixthmodification shown in FIG. 27.

Besides, in the above-mentioned embodiments, although the case isexplained where the plating pattern of each layer is different from eachother in configuration and dimension, it is not limited to this. Forexample, the present invention is also effective when only theconfiguration of the plating pattern mutually differs in each layer andthe area thereof is all equal. Namely, when the plating pattern in eachlayer has a remarkably different configuration from each other, growingdifference thereof may cause a considerable difference in thecomposition thereof even if the area of the plating pattern is equal toeach other. In the present invention, even if the plating pattern ineach layer has a different configuration from each other, difference incomposition thereof can be suppressed very small by forming the layersso as to include other auxiliary plating layers thereon in addition tothe plating patterns, respectively.

In the second embodiment as described above, although the case offorming a plurality of magnetic shielding layers all having the samecomposition to be used in a thin film magnetic head is explained, thepresent invention is not limited to this. For example, it is alsosuitable for formation of various plating patterns included in otherelectronic and magnetic micro devices, such as a thin film inductor, acommon mode filter or a magnetic random-access memory (MRAM).

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1. A method of plating for forming plating patterns of a plurality oflayers, comprising a step of forming a plating layer including theplating pattern in each of the plurality of layers, wherein area of theplating layer electrodeposited is constant in each of the plurality oflayers.
 2. The method of plating according to claim 1, wherein processof forming the plating layer in each of the plurality of layers includessteps of: forming a plating foundation layer, forming a resist frame andone or more auxiliary resist patterns on the plating foundation layer,forming the plating layer selectively on the plating foundation layerother than portions covered with the resist frame and the auxiliaryresist patterns, removing the resist frame and the auxiliary resistpatterns, and removing the plating layer other than the plating patternsurrounded by the resist frame, wherein sum total of area of the resistframe and the auxiliary resist patterns in each of the plurality oflayers is constant.
 3. The method of plating according to claim 1,wherein at least one of geometry and area of the plating pattern differsbetween the plurality of layers.
 4. The method of plating according toclaim 1, wherein a common plating bath is used for forming each platinglayer.
 5. The method of plating according to claim 1, wherein a commonplating bath is used for forming each plating layer so that each platinglayer has a uniform composition.
 6. The method of plating accordingclaim 1, wherein a plurality of the auxiliary resist patterns are formedsymmetrically with respect to the resist frame.
 7. The method of platingaccording to claim 1, wherein the resist frame and the auxiliary resistpatterns have a line width equal to each other.
 8. The method of platingaccording to claim 1, wherein each plating layer includes a plurality ofplating patterns.
 9. A method of manufacturing a micro device includingplating patterns of a plurality of layers, comprising a step of forminga plating layer including the plating pattern in each of the pluralityof layers, wherein area of the plating layer electrodeposited isconstant in each of the plurality of layers.